<!-- eslint-disable eqeqeq -->
<template>
  <div class="app-container">
    <h2 style="text-align: center;">发布新课程</h2>
    <el-steps :active="1" process-status="wait" align-center style="margin-bottom: 40px;">
      <el-step title="填写课程基本信息"/>
      <el-step title="创建课程大纲"/>
      <el-step title="提交审核"/>
    </el-steps>
    <el-form label-width="120px">
      <el-form-item label="课程标题">
        <el-input v-model="courseInfo.title" placeholder="示例：机器学习项目课：从基础到搭建项目视频课程。专业名称注意大小写"/>
      </el-form-item>
      <!-- 所属分类 -->
      <el-form-item>
        <!-- 一级分类 -->
        <el-select
          v-model="courseInfo.subjectParentId"
          placeholder="一级分类"
          @change="subjectLevelOneChanged">
          <el-option
            v-for="subject in subjectOneList"
            :key="subject.id"
            :label="subject.title"
            :value="subject.id"/>

        </el-select>
        <!-- 二级分类 -->
        <el-select
          v-model="courseInfo.subjectId"
          placeholder="二级分类">
          <el-option
            v-for="subject in subjectTwoList"
            :key="subject.id"
            :label="subject.title"
            :value="subject.id"/>
        </el-select>

      </el-form-item>
      <!-- 课程讲师 -->
      <el-form-item label="课程讲师">
        <el-select
          v-model="courseInfo.teacherId"
          placeholder="请选择">
          <el-option
            v-for="teacher in teacherList"
            :key="teacher.id"
            :label="teacher.name"
            :value="teacher.id"/>
        </el-select>
      </el-form-item>
      <el-form-item label="总课时">
        <el-input-number :min="0" v-model="courseInfo.lessonNum" controls-position="right" placeholder="请填写课程的总课时数" />
      </el-form-item >

      <el-form-item label="课程简介">
        <el-input v-model="courseInfo.description" placeholder=""/>

      </el-form-item>
      <!-- 课程封面上传 -->
      <el-form-item label="课程封面">
        <el-upload
          :show-file-list="false"
          :on-success="handleAvatarSuccess"
          :before-upload="beforeAvatarUpload"
          :action="BASE_API+'/eduoss/fileoss'"
          class="avatar-uploader">
          <img :src="courseInfo.cover">
        </el-upload>
      </el-form-item>

      <el-form-item label="课程价格">
        <el-input-number
          :min="0"
          v-model="courseInfo.price"
          controls-position="right"
          aria-placeholder="免费课程请设置为0元"/>

      </el-form-item>

      <el-form-item>
        <el-button
          :disabled="savaBtnDisabled"
          type="primary"
          @click="saveOrUpdate">保存下一步

        </el-button>
      </el-form-item>
    </el-form>
  </div>
</template>
<script>
import course from '@/api/edu/course'
import subject from '@/api/edu/subject'
export default {
  data() {
    return {
      savaBtnDisabled: false,
      courseInfo: {
        title: '',
        subjectId: '',
        teacherId: '',
        subjectParentId: '',
        lessonNum: 0,
        description: '',
        cover: '/static/03.jpg',
        price: 0
      },
      // 封装讲师数据
      teacherList: [],
      subjectOneList: [],
      subjectTwoList: [],
      BASE_API: process.env.BASE_API,
      courseId: ''
    }
  },
  // 路由发生变化，就会执行,监听
  watch: {
    $route(to, from) {
      this.init()
    }
  },
  created() {
    this.init()
  },
  methods: {
    init() {
      if (this.$route.params && this.$route.params.id) {
        this.courseId = this.$route.params.id
        this.getInfo()
      } else { // 添加操作
        this.courseInfo = {}
        this.courseInfo.cover = '/static/07.jpg'

        this.getListTeacher()
        // 初始化所有一级分类
        this.getOneSubject()
      }
    },
    // 根据id获得基本信息，为了返回上一页有数据
    getInfo() {
      course
        .getCourseInfoId(this.courseId)
        .then(response => {
          this.courseInfo = response.data.courseInfoVo
          // 1.初始化一级分类和二级分类
          subject.getSubjectList()
            .then(response => {
              // 获取所有一级分类并赋值
              this.subjectOneList = response.data.list
              // 遍历一级分类的数组
              for (var i = 0; i < this.subjectOneList.length; i++) {
                // 获取数组中每个一级分类
                var oneSubject = this.subjectOneList[i]
                // 拿每个一级分类的id和数据模型courseInfo.subjectParentId比较是否相等
                // eslint-disable-next-line eqeqeq
                if (oneSubject.id == this.courseInfo.subjectParentId) {
                  // 找到相等的那一个一级分类,获取到该一级分类下的所有二级分类并赋值
                  this.subjectTwoList = oneSubject.children
                }
              }
            })
          // 2.初始化所有讲师
          this.getListTeacher()
        })
    },
    // 成功之后得方法
    handleAvatarSuccess(response) {
      this.courseInfo.cover = response.data.url
    },
    // 上传之前得方法
    beforeAvatarUpload(file) {
      const isJPG = file.type === 'image/jpeg'
      const isLt2M = file.size / 1024 / 1024 < 2
      if (!isJPG) {
        this.$message.error('上传头像图片只能是 JPG 格式!')
      }
      if (!isLt2M) {
        this.$message.error('上传头像图片大小不能超过 2MB!')
      }
      return isJPG && isLt2M
    },

    // 通过遍历得二级,value是一级id
    // 点击某个一级分类后,能显示该一级分类下的所有二级分类
    subjectLevelOneChanged(value) { // value是传过来的一级分类id
      // 遍历所有分类,包含一级和二级
      for (var i = 0; i < this.subjectOneList.length; i++) {
        // 遍历得到的一级分类
        var oneSubject = this.subjectOneList[i]
        // 判断遍历得到的一级分类id和我们点击的一级分类id是否一样
        // eslint-disable-next-line eqeqeq
        if (oneSubject.id == value)
        // 获取该一级分类下所有的二级分类
        // eslint-disable-next-line brace-style
        { this.subjectTwoList = oneSubject.children }
        // 清空二级分类的id值
        this.courseInfo.subjectId = ''
      }
    },

    // 调用一级分类
    getOneSubject() {
      subject
        .getSubjectList()
        .then(response => {
          this.subjectOneList = response.data.list
        })
    },
    // 获得老师列表
    getListTeacher() {
      course
        .getListTeacher()
        .then(response => {
          this.teacherList = response.data.items
        })
    },
    // 添加课程
    addCourse() {
      course
        .addCourseInfo(this.courseInfo)
        .then(response => {
          this.$message({
            type: 'success',
            message: '添加课程基本信息成功'
          })
          this.$router.push({ path: '/course/chapter/' + response.data.courseId })
        })
    },
    // 修改课程
    updateCourse() {
      course.updateCourseInfo(this.courseInfo)
        .then(response => {
          this.$message({
            type: 'success',
            message: '修改课程基本信息成功'
          })
          this.$router.push({ path: '/course/chapter/' + this.courseId })
        })
    },
    saveOrUpdate() {
      if (!this.courseInfo.id) {
        this.addCourse()
      } else {
        this.updateCourse()
      }
    }
  }

}
</script>
